A first demonstration of realized selection response for fillet yield in fish, in rainbow trout oncorhynchus mykiss

A first demonstration of realized selection response for fillet yield in fish, in rainbow trout oncorhynchus mykiss. 13. International Symposium for Genetics in Aquaculture (ISGA XIII

Parametres genetiques d'une population d'escargots Petits-Gris. Synthese de 3 annees d'observations

National audienc

X-ray quantitative texture analysis on Helix aspersa aspera (Pulmonata) shells selected or not for increased weight

Chantier qualité GAInternational audienceX-ray Quantitative Texture Analysis (QTA) results are examined for the outer aragonitic shell layers of Helix aspersa aspersa (Müller, 1774) to probe the relevance of the approach to non-flat surfaces. Two sets of H. aspersa aspersa were studied, for a total of 29 samples. Quantitative texture analysis showed that although the nature of the texture present was roughly constant, the textural strength varied significantly among specimens because of biologically inherited surface irregularities. A statistical analysis showed that textural strength exhibited larger standard deviations for snails selected for greater shell weight than for control snails. The H. aspersa aspersa aragonite texture is the same as observed in previous studies, with shell growth directions. This texture causes elastic behavior of the mineral part of the shell, which accommodates moderate shear and compression. We furthermore determine that the colored bands at the shell surface were aligned with the crystal directions

Genetic and environmental variability of adult size in some stockes of the edible snail, Helix aspersa

6 tablesInternational audienc

Evolution of genetic variability in a population of the edible snail, Helix aspersa Muller, undergoing domestication and short-term selection

International audienc

Génétique quantitative des caractères de croissance chez l'escargot comestible, Helix aspersa Müller

National audienceGenetic parameters of adult weight, age at maturity (adult age), weight after hibernation and relative loss of weight during hibernation were estimated in a population of edible snails (Helix aspersa Müller). Eight thousand four hundred and eighthy three animals were sampled from 143 pairs for adult weight, 4 333 from 87 pairs for adult age and 2 256 from 123 pairs for traits after hibernation. An animal model taking into account all the relationships was used to estimate genetic parameters. Estimates were also computed from the covariances between full-sibs and parent offspring regressions to assess possible non-additive genetic effects. Heritabilities were high except for relative loss of weight during hibernation. Estimates from the animal model were 0.48 ± 0.04 for adult weight, 0.40 ± 0.05 for adult age, 0.40 ± 0.05 for weight after hibernation and 0.12 ± 0.03 for relative loss of weight during hibernation. Adult weight and adult age were neither phenotypically nor genetically correlated (0.05 and 0.003 ± 0.07, respectively). A substantial maternal effect, especially on adult weight was found.Les paramètres génétiques de plusieurs caractères de croissance ont été estimés dans une population d’escargots Petit-Gris (Helix aspersa Müller). Il s’agit du poids adulte, de l’âge à maturité (âge adulte), du poids après hibernation et de la perte relative de poids lors de l’hibernation. Le nombre d’observations collectées se répartit ainsi : 8 483 animaux issus de 143 couples pour le poids adulte, 4 333 issus de 87 couples pour l’âge adulte et 2 256 issus de 123 couples pour les caractères mesurés après hibernation. Afin de tenir compte de toutes les relations de parenté, nous avons utilisé un modèle animal pour estimer les paramètres génétiques. Ils ont également été estimés à partir des covariances entre plein-frères et de la régression parents-descendants. Cela nous a permis de discuter des effets génétiques non additifs. Tous les caractères sauf la perte de poids relative lors de l’hibernation révèlent des héritabilités élevées. Les estimations issues du modèle animal sont de 0,48 ± 0,04 pour le poids adulte, 0,40 ± 0,05 pour l’âge adulte, 0,40 ± 0,05 pour le poids après hibernation et 0, 12 ± 0 03 pour la perte relative de poids lors de l’hibernation. Il n’y a pas de corrélation (ni phénotypique, ni génétique) significative entre le poids et l’âge adultes (0,05 et 0,003 ± 0,07, respectivement). Nous avons également mis en évidence un effet maternel important, en particulier sur le poids adulte

Snail breeding and quantitative genetics

National audienc